“You then start to wonder, am I actually in a fight for my life? Yeah, I was. It is that simple, because I believed him.”

Police were called to a wine bar in Highworth at midnight in July 2017 to reports the man had been threatening and shouting at his girlfriend. By the time PC Baker and another officer arrived the man, Joseph Theobald, had returned home.

The officers escorted his partner to the couple’s flat. When they got there, the Theobald was standing at the far end of the room. “There was anger written all over his face,” said PC Baker.

Footage from a CCTV camera worn by PC Baker showed him shouting at the officers to get out of his house.

When he pushed at his girlfriend’s hands, the officers tried to restrain him. PC Baker said: “That’s where it all went wrong. He seemed to have superhuman strength or no just bearing of pain at all.”

In the struggle, the other officer sprayed PAVA – a type of pepper spray – into Theobald’s eyes. It hit PC Baker in the face.

Eyes streaming, the male officer tried to pin the suspect against the wall. They tumbled into the kitchen. He recalled: “I find my head being driven towards a kitchen sink area. There’s a large kitchen knife that’s blade up. I’m thinking this could go horribly wrong.”

Theobald bit PC Baker and strangled the other officer. Across Swindon, police officers could hear the struggle over their radios as they raced towards Highworth.

PC Sean Magee said: “All you could hear were these high-pitched screams. It was bloodcurdling.”

PC Rob Dent said it sounded as if the life was being drained the strangled constable.

Insp Mark Andrews, chairman of Wiltshire Police Federation, called on judges to hand out longer sentences for those convicted of assault emergency workers: “I believe, as does the Police Federation, that anyone who assaults a police officer should go to prison.”

Theobald, who works for Newsquest, admitted causing actual bodily harm and was sentenced to 14 months imprisonment suspended for two years.

Yesterday, he said: "I am thoroughly ashamed of my actions in relation to both PC Diamon and PC Mat Baker.

"Having consumed an inordinate quantity of alcohol, I acted well out of character and became extremely aggressive and violent towards two upstanding and no-doubt dedicated, hardworking police officers.

"Since the incident, I have taken many steps to account for my disgusting behaviour and address my destructive relationship with drink."

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